Add a custom section to a Wanderlog trip

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only declare the write/non-destructive/non-idempotent profile; the description adds real behavior beyond that — the section is created empty, the heading must be unique among undated sections, and duplicate or ambiguous targets are rejected without making any change. It also states what is returned (heading and position), which the annotations do not cover.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short paragraphs, front-loaded with the core action, then usage, then constraints and return value. No filler sentences; each one carries distinct information an agent needs.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a three-parameter mutation tool with no output schema, the description covers purpose, follow-on workflow, the failure/atomicity condition, and the return payload. An agent has everything needed to call it correctly and to interpret the result.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is already 100%, so the baseline would be 3; the description earns more by explaining that the created heading becomes the identifier passed as the 'section' parameter to wanderlog_add_place, and by tying the uniqueness constraint to the heading argument. The after_section insertion behavior is only implied in the description, since the schema documents it directly.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Adds a new custom section to a Wanderlog trip itinerary') and immediately clarifies that sections are containers for places, notes and blocks, which separates it from wanderlog_add_place and wanderlog_add_note in the sibling list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete use cases (thematic grouping such as 'Food & Drink', 'Day Trips', or extra place lists beyond the default 'Places to visit') and routes the agent forward to wanderlog_add_place / wanderlog_add_note / wanderlog_add_checklist for filling the section. It does not contrast with wanderlog_update_section or wanderlog_delete_section, so the boundary against those siblings is left implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.